Cygwin (For Windows only) and Xcrysden need to be installed for band structure calculation and plotting. Cygwin is a virtual Linux platform on Windows, from which you can connect to high-performace comupters. Xcrysden is a plotting software which can plot crystal structure, Fermi surface, etc.
Install cygwin (Windows users only):
You can get it from near the bottom there is a link that says “Install or update now!”
You'll get a choice of packages to install. Things not to miss:
emacs, pico, vi (these are text editors)
gnuplot (you might want to plot things)
openssh (need this to connect to severs)
all the X stuff (this is needed for graphics, i.e. plotting)
If you miss any packages, don't worry. You can install them later
After installing, find and run xterm (C:\cygwin\Cygwin.bat).
Linux commands (skip this if you know already)
pwd - view the name of the current directory you are in
ls - list files and subdirectories in the current directory
mkdir dir_name - make a new directory
cd dir_name - change directory from current directory to another.
more file_name - view the content of a file
cp file_1 file_2 - copy file_1 to file_2
To be able to run gnuplot or other plotting software from other machines, you will need to run ssh as 'ssh -X'. The -X allows for graphics to be sent back and forth.
.tar files are extracted using `tar xvf filename`, .tar.gz files are extracted using `tar zxvf filename`
Install Xcrysden:
Download it from
Pick the version appropriate to your OS and download. It is convenient to use “wget DOWNLOAD_LINK”
If you're running linux, get the statically linked one, and for installation follow the directions in
Follow the instructions under “A bit longer installation instructions.” It's important that you run the xcConfigure script and that you source .bashrc or .cshrc file after you're done
Under windows, it requires CYGWIN. Download it and extract it the .tar file. Follow the same instruction of installation.
You can check if it is successfully installed by typing “xcrysden” and checking it starts or not.
Xcrysden examples:
Download
Unpack it using tar zxvf FeO2.tar.gz
Start xcrysden (you should just be able to type it) in the newly created directory
Go to File → Open Structure → Open XSF File and open ch.plot
You should see a box with a linear FeO2 molecule in it. Play around with the various settings, try changing the colors, making axes, zoom in, etc.
Go to Tools → Data Grid and hit ok. XcrySDen will import the charge density
On Tab 1, have XC plot an isosurface. Try a number of values.
Download
Unpack it by tar zxvf copper.tar.gz . Three files, copper.xsf, copper.bxsf and Cu.dos. Copper.xsf contain crystal structure and charge density. Repeat plotting charge density of the previous system.
Copper.bxsf has Fermi surface information. Load Open BXSF File and open copper.bxsf. Hit OK for Fermi energy. And you can see that Fermi energy only cross band number 6. So choose number 6, and hit Selected, and you can see Fermi surface of copper.
Use gnuplot to plot DOS of copper by p ‘Cu.dos’ u 1:2 w l . We can see thatat Fermi energy (12.14 eV), DOS is not zero.
For something more interesting, try plotting the data found in . This is the Fermi level density of states for BaFe2As2 (a superconductor)